The application of a work platform forces to the pump jack “L” frame result in significant stresses in the material and fasteners located at the connection of the vertical and horizontal members. FIG. 2 shows that the “L” frame design currently employed by pump jack manufacturers utilizes outwardly opened, laterally opposing, “C” shaped channels for both the vertical 10 and horizontal 11 frame members. At the connection of the vertical and horizontal members, the flange of the vertical member 10 must be notched 12, or removed as shown in FIG. 3, to facilitate the connection of the horizontal member 11. The notching 12, or removal, of the flange in this area weakens the frameworks at its most structurally critical location in two ways:                1. The removal of flange material in the area local to the most significant stresses.        2. The notching process generates a point where stresses are concentrated. This point 13 is located at the corner of the notch 12. This point 13 of concentrated stress is commonly referred to as a stress riser.        
As a result, under test loads, the “L” frame vertical member 10 will fail in this structurally critical area.